1. Field of the Invention
The present invention relates to a wire dot printer head of wire dot printer, and more particularly, to a wire dot printer head having an armature stopper for contact with an armature rocking from a printing position to a standby position.
2. Discussion of the Background
Conventionally known is a wire dot printer head, in which printing wire is coupled to an armature to rock between a printing position and a standby position. When the armature rocks to the printing position, an end of the wire is collided against a print sheet, thereby printing is performed.
This wire dot printer head has an armature stopper with which the armature comes into contact when it rocks from the printing position to the standby position. The armature stopper absorbs a shock upon rocking of the armature to the standby position, suppresses a rebound of the armature, and prevents occurrence of inconvenience such as overstriking or poor feeding of ribbon which is caught due to rebound. As an example of armature stopper, a structure where a rubber elastic sheet and a stainless plate are overlapped with each other is known. This armature stopper is provided in a direction where the armature rocked to the standby position comes into contact with the stainless plate.
However, in recent years, printing speed and printing pressure have been increased, and in accordance with such high printing speed and high printing pressure, an impact of collision between the armature stopper and the armature that rocked to the standby position has been increased.
As the impact of collision between the armature and the armature stopper increases, a part of the stainless plate to be collided against the armature as a part of the armature is cut away, broken or deformed. If the part to be collided against the armature wears, broken or deformed, printing stroke of the armature is changed, and variation occurs in printing timing and printing pressure in each wire, thus printing quality is degraded.
Further, if the shock of the collision between the armature and the armature stopper increases, the plate vibrates due to the shock, and the vibration of the plate is transmitted to other armatures. In the other armature to which the vibration is transmitted, variation occurs in rocking timing of the rocking with respect to the printing position and printing pressure, thus printing quality is degraded.
Accordingly, an object of the present invention is to prevent the abrasion, breakage or deformation of the portion of the armature stopper to be in contact with the armature when the armature rocking from the printing position to the standby position comes into the armature stopper.
Another object of the present invention is to suppress vibration of the armature stopper when the armature rocking from the printing position to the standby position comes into contact with the armature stopper.
These objects of the present invention are attained by a novel wire dot printer of the present invention.
Accordingly, in the novel wire dot printer head of the present invention, an armature stopper with which an armature rocking from a printing position to a standby position comes into contact is formed by integrating an elastic plate and a hard plate with each other. The hard plate is made of material having high abrasion resistance for prevention of scrape, breakage or deformation even by collision by the armature rocking to the standby position.